Yes. The RKI GX-3R (SKU 72-RA-C) is purpose-built as a confined space 4-gas monitor, simultaneously detecting the four gases required for confined space entry — combustibles (LEL), oxygen (O2), hydrogen sulfide (H2S), and carbon monoxide (CO). It's the world's smallest and lightest 4-gas monitor at just 3.52 oz (about 100 g) and 2.2" x 2.55" x 1.02", so it fits within a worker's OSHA breathing zone (a 10-inch radius around the nose and mouth) — something traditionally only single-gas monitors were small enough to do. It runs 25 hours on a Li-ion charge, is rated IP66/68 for dust and water resistance, survives a 23 ft drop, and carries ATEX, CSA, IECEx, and MED approvals. It ships with free shipping from Industrial Safety Products.

The RKI GX-3R (72-RA-C) simultaneously detects four gases: combustibles (LEL) 0–100% LEL in 1% increments, oxygen (O2) 0–40% Vol in 0.1% increments, hydrogen sulfide (H2S) 0–200 ppm in 0.1 ppm increments, and carbon monoxide (CO) 0–2,000 ppm in 1 ppm increments. The LEL sensor uses catalytic combustion; O2, H2S, and CO use electrochemical (EC) sensing. An H2-compensated CO sensor is also available to reduce hydrogen cross-interference. Response time is within 30 seconds (T90).

The RKI GX-3R (72-RA-C) carries ATEX, CSA, IECEx, and MED approvals, making it suitable for use in hazardous (explosive-atmosphere) locations across confined spaces, refineries, oil and gas, utilities, and water/wastewater. It is also rated IP66/68 for dust and water resistance (tested to 2 m for 1 hour) and withstands a 23 ft drop. These certifications are listed on the Industrial Safety Products product page.

The RKI GX-3R is the world's smallest and lightest 4-gas monitor, weighing just 3.52 oz (about 100 g) and measuring 2.2" W x 2.55" H x 1.02" D — small enough to clip inside a worker's breathing zone. Its rechargeable Li-ion battery delivers about 25 hours of operation on a 3-hour full charge. It's built tough with an impact-resistant body and removable rubber boot, an IP66/68 dust- and water-resistant rating, and a 23 ft drop height. It's backed by a 3-year warranty and ships with free shipping from Industrial Safety Products.

The RKI GX-3R's LEL (combustible gas) sensor has a unique design with two active filaments in a single sensor to increase resistance to silicone poisoning — a common cause of combustible-sensor failure. If one filament becomes poisoned, the second filament takes over, extending reliable detection. The sensor uses catalytic combustion and reads 0–100% LEL in 1% increments, with response within 30 seconds (T90).

The non-compliance indicator on the RKI GX-3R is a safety-supervisor feature: the instrument flashes its 3 LED lights once every 30 seconds whenever the unit has not been bump tested, calibration is due, or a gas alarm event has occurred. The LEDs keep flashing until the non-compliance condition is resolved, giving supervisors an at-a-glance way to spot units that are out of compliance. The 30-second interval is adjustable.

The RKI GX-3R (72-RA-C) has three alarm types — audible, visual (flashing LEDs), and vibration — so alerts are noticeable even in loud or high-visibility-limited environments. It offers 3 user-adjustable alarm levels plus STEL, TWA, and overscale alarms, and O2 increasing/decreasing alarms. The gas-alarm buzzer sounds at 100 dB at 30 cm. Trouble alarms cover sensor disconnection, low battery, circuit error, and calibration range error.

The RKI GX-3R uses diffusion sampling as standard, meaning gas reaches the sensors naturally without a built-in pump — ideal for personal, breathing-zone monitoring. For remote or pre-entry sampling of a confined space, an optional hand aspirator or a clip-on motorized pump can be added. Sampling is controlled with simple 2-button operation (POWER/MODE and AIR).

Because the RKI GX-3R gives you four gases in a device smaller than many single-gas monitors. OSHA defines the breathing zone as a 10-inch radius around the worker's nose and mouth, and traditionally only a single-gas monitor was small enough to practically wear there. At 3.52 oz and 2.2" x 2.55" x 1.02", the GX-3R lets a worker monitor LEL, O2, H2S, and CO simultaneously right in the breathing zone — the protection of a 4-gas monitor with the wearability of a single-gas unit.

The H2-compensated CO sensor is an optional carbon monoxide sensor for the RKI GX-3R that reduces cross-interference from hydrogen (H2), giving more accurate CO readings in environments where hydrogen is present (such as around battery charging or certain industrial processes). Both the standard CO and H2-compensated CO sensors read 0–2,000 ppm in 1 ppm increments. Sensors and filters on the GX-3R are field-replaceable.

The RKI GX-3R (72-RA-C) comes standard with an alligator clip, a protective rubber boot, a charger, and a calibration adapter, and it's backed by a 3-year warranty. It features datalogging (user ID, station ID, calibration and bump-test history, and alarm events), field-replaceable sensors and filters, and a stealth mode for law enforcement. You can buy it from Industrial Safety Products (industrialsafetyproducts.com) with free shipping.